L1969 to E 1970 Big Block Dipstick

[Joe L.]

Re: L1969 to E 1970 Big Block Dipstick

I have a Feb 18 built 1970 non-air 454. Dipstick has flattend handle with black plug and measures 24" to Add line. Pretty sure its original. Will check today for any other part numbers or letters and will post.

Mark-----


Thanks. Any other information you can come up with will be helpful. It's starting to look like this "black plug" dipstick was some sort of early version of the 3981088. Most likely it had some other and unknown part number, though. I don't think it could be the "mystery dipstick", GM #3959158, because the 24" measurement doesn't work for that dipstick.

Could you measure the dipstick tube from the point of the lower "collar" (where it seats on the oil pan "nipple") to the upper end?

[Mark Z.]

Re: L1969 to E 1970 Big Block Dipstick

Joe,
Using a string measured 19 3/4" from where the lower tube seats against the oil pan to the top. If that isn't what you're looking for let me know.

[Kenneth B.]

Re: L1969 to E 1970 Big Block Dipstick

Joe, attached are photos of my LS5 dipstick. The motor was built ion 12/19/69 and the car was built on 1/9/70. It measures 24 inches to the add mark. The button fell off at some point or was never there to begin with. The car is a Bowtie car. In the engine bay it sticks up pretty high. I can get more photos if you wish. Chris

JOE
Mine is just like this one with no button & is a 70 with AC & SN 7601> has the original motor.
KEN

[Joe L.]

Re: L1969 to E 1970 Big Block Dipstick

Joe,
Using a string measured 19 3/4" from where the lower tube seats against the oil pan to the top. If that isn't what you're looking for let me know.

Mark------

That sounds pretty close to the measurement I get from a known GM #3981089 dipstick tube which is the tube that was supposed to be used with the GM #3981088 dipstick.

So, you either have a GM #3981088 dipstick which was made to a specification other than that shown on the GM #3981088 drawing OR there was another dipstick of unknown part number that preceded the 3981088 but still used the GM #3981089 dipstick tube.

[Joe L.]

Re: L1969 to E 1970 Big Block Dipstick

JOE
Mine is just like this one with no button & is a 70 with AC & SN 7601> has the original motor.
KEN

Ken------


I think what may have happened with the button is that the way these loop handles were formed, the circular end of the tube that was supposed to retain the plastic button got distorted to some degree. That, I expect, resulted in poor retention of the button and its subsequent falling out.

[Kenneth B.]

Re: L1969 to E 1970 Big Block Dipstick

Ken------


I think what may have happened with the button is that the way these loop handles were formed, the circular end of the tube that was supposed to retain the plastic button got distorted to some degree. That, I expect, resulted in poor retention of the button and its subsequent falling out.

Joe I agree. It looks like there is a crease under the handle which would destort the ID. for the button My other two 70 lt-'S have a a black button with no crease. Bothe FEB. builds
KEN

[D S.]

Re: L1969 to E 1970 Big Block Dipstick

Ken------


I think what may have happened with the button is that the way these loop handles were formed, the circular end of the tube that was supposed to retain the plastic button got distorted to some degree. That, I expect, resulted in poor retention of the button and its subsequent falling out.

There are reportedly two versions of the 1970 Corvette LS-5 dipsticks with black buttons, one short one and a longer one that some believe came on C-60 equipped cars. That was dispelled because the short and long ones were both found on C-60 equipped cars. Now I am wondering if the short ones were too close to the exhaust manifold making the handles too hot and a longer dipstick and longer tube was issued to raise it higher. For some reason the ones with the black buttons or plugs seem to have a higher "fall-out" rate
than the ones with red buttons or plugs.

[Joe L.]

Re: L1969 to E 1970 Big Block Dipstick

There are reportedly two versions of the 1970 Corvette LS-5 dipsticks with black buttons, one short one and a longer one that some believe came on C-60 equipped cars. That was dispelled because the short and long ones were both found on C-60 equipped cars. Now I am wondering if the short ones were too close to the exhaust manifold making the handles too hot and a longer dipstick and longer tube was issued to raise it higher. For some reason the ones with the black buttons or plugs seem to have a higher "fall-out" rate
than the ones with red buttons or plugs.

Scott------


The early 1970 454 dipsticks and dipstick tubes were supposed to be, basically, the same as those used for all 1965-69 Corvette big blocks. So, if they were a problem for 1970, then they would have been a problem for 65-69. However, the longer dipstick and tube, whether of GM #3981088 and 3981089, respectively, or some other unknown part numbers should have been less of a problem than any of the earlier because they were longer and more easily accessed.

[D S.]

Re: L1969 to E 1970 Big Block Dipstick

Scott------


The early 1970 454 dipsticks and dipstick tubes were supposed to be, basically, the same as those used for all 1965-69 Corvette big blocks. So, if they were a problem for 1970, then they would have been a problem for 65-69. However, the longer dipstick and tube, whether of GM #3981088 and 3981089, respectively, or some other unknown part numbers should have been less of a problem than any of the earlier because they were longer and more easily accessed.

Mine is the longer version and I like it up high. 6" lower and it would be a lot hotter to handle.
Joe, you have sure raised some interesting issues with this. I assume that the dipsticks in the C-2 big blocks were red button until late '69 to early 1970 big blocks, right? They became black buttons in that period but up until when in 1970 or 1971 did they become red button?

[Joe L.]

Re: L1969 to E 1970 Big Block Dipstick

All-------


One other thing that surprises me about this 1970 black plug dipstick situation: the plastic plugs in the dipsticks were there to allow the assembly line workers the ability to quickly identify the correct dipstick for the application. They had no other purpose. Well, for 1970, the Corvette small block engines also used a dipstick with a black plug. So, with big blocks also using a black plug, the whole intent of the identifying colored plugs would be lost.

So, one might theorize that maybe someone discovered this problem and the color of the big block dipstick plug was changed to red. But, that did not happen. The drawing for the GM #3981088 dipstick was created on September 9, 1969 and specified a red plug. While there were several minor revisions to the drawing, none affected the color of the plug. So, as far as I can tell, it was always red.

[Joe L.]

Re: L1969 to E 1970 Big Block Dipstick

Mine is the longer version and I like it up high. 6" lower and it would be a lot hotter to handle.
Joe, you have sure raised some interesting issues with this. I assume that the dipsticks in the C-2 big blocks were red button until late '69 to early 1970 big blocks, right? They became black buttons in that period but up until when in 1970 or 1971 did they become red button?

Scott------


No, while the 1965-69 big block dipsticks were all of about the same dimensions and 1965-E69 dipsticks and tubes were interchangeable, there were 2 different colored plugs used.

1965-E67 used a "salmon" colored plug (GM #3860316);

L1967-E69 used a white plug (GM #3925520);

L69-E70 was supposed to have used a dipstick that had dimensions very similar to the 1965-E69 dipsticks and a tube the same as used with all those dipsticks. I have no idea what colored plug this dipstick used. The black plugged dipsticks don't have "add" and "full" dimensions anything like the L69-E70 dipstick, GM #3959158, was supposed to have. So, I can't see how the black plugged dipstick could have been a GM #3959158.

L70-74 used a red plug (GM #3981088).

[D S.]

Re: L1969 to E 1970 Big Block Dipstick

Joe, quite honestly I wish they had stayed red. Do you realize how hard it is to find a round, black plastic rod that size to replace the those that are lost let alone the correct dipstick? I have two service replacement 3981088s that I could rob the red plugs from.

[Donald S.]

Re: L1969 to E 1970 Big Block Dipstick

Joe,

I've attached pictures of the dipstick that came on my November '69 435. As I mentioned, since I'm not the original owner, I can't vouch that it's original. It certainly matched the "patina" of the rest of the parts on the engine which made me to believe it had not been replaced. However when I started to slowly restore the car, I went with what the J/G mentioned as "correct".
The end of the loop is crimped shut, so there was no colored plug installed. A close examination showed no part number at all.
Also, the measurement is from the top of the bell. Your thoughts?

Don

[Joe L.]

Re: L1969 to E 1970 Big Block Dipstick

Joe,

I've attached pictures of the dipstick that came on my November '69 435. As I mentioned, since I'm not the original owner, I can't vouch that it's original. It certainly matched the "patina" of the rest of the parts on the engine which made me to believe it had not been replaced. However when I started to slowly restore the car, I went with what the J/G mentioned as "correct".
The end of the loop is crimped shut, so there was no colored plug installed. A close examination showed no part number at all.
Also, the measurement is from the top of the bell. Your thoughts?

Don

Don-----


Thanks for the photos. I think this is an original dipstick and it may very well be the "mystery dipstick", GM #3959158. If the measurement were taken from the bottom of the bell at the seat (where most GM dipstick upper measurements were taken from), it would put the "add" mark right at about 19", just where it's supposed to be for the GM #3959158 dipstick.

The extreme offset on the handle section might have been an early attempt at correcting the access difficulty for the handle. When it didn't work out, perhaps they decided that a longer tube and dipstick was the best way to go and along came the "black plug" dipstick, the "red plug" dipstick, and the GM #3981089 dipstick tube.

I'd sure like to see more of these, though, on late 1969's (and early 70's).